Display control method and display control device

ABSTRACT

In a display control method, a first information image is displayed on a head-up display. The first information image includes a first vehicle icon which is a figure indicating a vehicle, and a first character string arranged above the first vehicle icon. A second information image is displayed on a meter display. The second information image includes a second vehicle icon which is a figure indicating a vehicle, and a second character string which is arranged below the second vehicle icon, and includes the first character string.

TECHNICAL FIELD

The present invention relates to a display control method and a displaycontrol device.

BACKGROUND

Conventionally, a technique is known by which information is displayedto a driver of a host-vehicle by using a head-up display and a meterdisplay (for example, Japanese Unexamined Patent Application PublicationNo. 2010-221730). Japanese Unexamined Patent Application Publication No.2010-221730 discloses contents in which when an image is displayed onthe head-up display, the same image as the head-up display is displayedon the meter display.

SUMMARY

A display position of an image on a head-up display, and a displayposition of an image on a meter display are different. Therefore,visibility characteristics of a driver relative to the images aredifferent between the head-up display and the meter display. If the sameimage is displayed on each of the head-up display and the meter display,as in the technique described in Japanese Unexamined Patent ApplicationPublication No. 2010-221730, the driver may not be able to recognizenecessary information.

The present invention is made in view of the above problem, and anobject of the present invention to provide a display control method anda display control device which enable a driver to appropriately graspinformation from a head-up display and a meter display.

In a display control method according to one aspect of the presentinvention, a first image is displayed on a head-up display. The firstimage includes a first vehicle icon that is a figure indicating avehicle, and a first character string arranged above the first vehicleicon. Further, in the display control method, a second image isdisplayed on a meter display. The second image includes a second vehicleicon which is a figure indicating a vehicle, and a second characterstring that is arranged below the second vehicle icon, and includes thefirst character string.

According to the present invention, a driver can properly graspinformation from a head-up display and a meter display.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a control system applied with adisplay control device according to the present embodiment;

FIG. 2 is an explanatory diagram schematically showing a scene ahead ofa driver's seat of a host-vehicle;

FIG. 3 is an explanatory diagram for explaining a first informationimage and a second information image;

FIG. 4A is an explanatory diagram for showing a series of movements froma first lane to a second lane of a host-vehicle in a situation ofovertaking a preceding vehicle by the automatic lane change proposed bya system;

FIG. 4B is an explanatory diagram for showing a series of movements froma second lane to a first lane of a host-vehicle in a situation ofovertaking a preceding vehicle by the automatic lane change proposed bya system;

FIG. 5A is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 5B is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 5C is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 5D is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 5E is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 6A is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 6B is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 6C is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 6D is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 6E is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change proposed by a system is performed;

FIG. 7 is an explanatory diagram for showing a series of movements froma third lane to an exit path of a host-vehicle in a situation ofperforming the automatic lane change along a route;

FIG. 8A is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8B is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8C is an explanatory diagram showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8D is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8E is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8F is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8G is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8H is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 8I is an explanatory diagram for showing an example of a firstinformation image and a second information image displayed when theautomatic lane change is performed along a route;

FIG. 9 is an explanatory diagram for showing an example of a secondinformation image; and

FIG. 10 is an explanatory diagram for showing an example of a firstinformation image and a second information image in the case of thetransition from a hands-on mode to a hands-off mode.

DETAILED DESCRIPTION

An embodiment of the present invention will be described below withreference to the drawings. In the drawings, the same parts are denotedwith the same reference numerals, and description thereof is omitted.

Descriptions will be given by applying a display control device and adisplay control method according to the present embodiment to a controlsystem (a vehicle control system) that controls the behavior of ahost-vehicle, and performs automatic driving. The automatic drivingmeans, for example, a state in which at least one of actuators, such asa brake, an accelerator, and a steering is controlled without anoperation by an occupant. Therefore, other actuators may be actuatedthrough the operation by the occupant. Further, the automatic drivingmay be a state in which any control such as acceleration/decelerationcontrol and lateral position control is performed. In the presentembodiment, manual driving means, for example, a state in which anoccupant operates the brake, accelerator, and steering. The host-vehiclemay be capable of switching between the automatic driving and the manualdriving.

An example of the automatic driving is the automatic lane change. Theautomatic lane change means that the control system controls thebehavior of the host-vehicle, so that the host-vehicle changes a lanefrom a host-vehicle lane on which the host-vehicle travels, to one ofthe right and left adjacent lanes adjacent to the host-vehicle lane.

A configuration of the control system will be described with referenceto FIGS. 1 and 2 . The control system includes a controller 10, ahost-vehicle position estimating device 20, a map acquisition device 21,a surrounding information detection device 22, a vehicle speed sensor23, a steering switch 24, a touch sensor 25, and a winker switch 26.Further, the control system includes a steering actuator 30, anaccelerator pedal actuator 31, and a brake actuator 32. Still further,the control system includes a meter display 35 and a head-up display 40.

In the interior of the host-vehicle applied with the control system, asteering 1 is arranged ahead of a driver, and an instrument panel 3 isarranged ahead of the steering 1. The instrument panel 3 is providedwith a meter unit 5 for displaying, to the driver, a meter of thehost-vehicle. A windshield 4 is arranged ahead of the instrument panel3.

The controller 10 is a general-purpose microcomputer including a CPU (acentral processing unit), a memory, and, an input/output unit. Themicrocomputer is installed with a computer program (a display controlprogram, and a control program) for causing the microcomputer tofunction as a display control device, and the control system. Byexecuting the computer program, the microcomputer functions as aplurality of information processing circuits in the control system. Thepresent embodiment shows an example in which the software implements theplurality of information processing circuits in the control system.However, it is also possible to configure the information processingcircuits by preparing dedicated hardware for executing each informationprocess described later. Further, the plurality of informationprocessing circuits may be constituted by individual hardware. Detailsof the plurality of information processing circuits of the controller 10will be described later.

The host-vehicle position estimating device 20 measures an absoluteposition of the host-vehicle by using position estimation techniques,such as GPS (global positioning system) and odometry. The host-vehicleposition estimating device 20 uses a position detection sensor tomeasure an absolute position of the host-vehicle, that is, a position ofthe host-vehicle relative to a predetermined reference point, a vehiclespeed, an acceleration, a steering angle, and an attitude. Thehost-vehicle position estimating device 20 includes sensor for acquiringthe behavior of the host-vehicle, such as a GPS receiver, inertialnavigation equipment, sensors provided to a brake pedal, and anaccelerator pedal, a wheel speed sensor and a yaw rate sensor, a laserradar, a camera, and the like. The host-vehicle position estimatingdevice 20 outputs the measured position information of the host-vehicleto the controller 10.

The map acquisition device 21 acquires map information showing astructure of a road on which the host-vehicle travels. The mapinformation acquired by the map acquisition device 21 includesinformation on a road structure such as an absolute position on eachlane, the relationship on how lanes are connected, and the relationshipon relative positions, traffic rules, road signs, and the like. The mapacquisition device 21 may have a map database storing the mapinformation, or alternatively may acquire the map information from anexternal map data server by using cloud computing. Further, the mapacquisition device 21 may acquire the map information by usingvehicle-to-vehicle communication, or vehicle-to-road communication. Themap acquisition device 21 outputs the acquired map information to thecontroller 10.

The surrounding information detection device 22 includes a plurality ofdifferent kinds of object detection sensors mounted on the host-vehicle.The object detection sensors are, for example, a laser range finder, alaser radar, a millimeter wave radar, a camera or the like. Thesurrounding information detection device 22 detects objects around thehost-vehicle by using the object detection sensors. The surroundinginformation detection device 22 detects moving objects including othervehicles, motorcycles, bicycles, and pedestrians, and stationary objectsincluding parked vehicles. For example, the surrounding informationdetection device 22 detects positions, attitudes (yaw angles), sizes,speeds, accelerations, jerks, decelerations, and yaw rates of the movingobject and the stationary object relative to the host-vehicle. Thesurrounding information detection device 22 may acquire surroundinginformation by using the vehicle-to-vehicle communication, orvehicle-to-road communication. The surrounding information detectiondevice 22 outputs the detected information to the controller 10.

The vehicle speed sensor 23 detects a vehicle speed of the host-vehicle.The vehicle speed sensor 23 outputs, to the controller 10, the detectedvehicle speed of the host-vehicle.

The steering switch 24 outputs an operation signal according to anoperation by the driver. The steering switch 24 is provided to thesteering 1. The steering switch 24 outputs, to the controller 10, theoperation signal according to the operation by the driver.

The touch sensor 25 is provided to the steering 1, and detects that adriver's hand touches the steering 1. As the touch sensor 25, acapacitance type sensor for detecting a change in the capacitance can beused. If the driver's hand touches the steering 1, the touch sensor 25outputs a predetermined detection signal to the controller 10.

The winker switch 26 is a switch which outputs an actuation signal foractuating a winker (a direction indicator) 34, and is operated by thedriver. After being operated by the driver, the winker switch 26 outputsthe actuation signal of the winker 34 to the controller 10.

The steering actuator 30 controls a steering angle of the steering 1.The steering actuator 30 is controlled by the controller 10.

The accelerator pedal actuator 31 controls the stepping amount of anaccelerator pedal. The accelerator pedal actuator 31 is controlled bythe controller 10.

The brake actuator 32 adjusts the stepping amount of the brake pedal.The brake actuator 32 is controlled by the controller 10.

The meter display 35 is arranged to the meter unit 5. The meter display35 displays a predetermined image such that the driver can visuallyrecognize the image. The driver can recognize various pieces ofinformation from the image displayed on the meter display 35. The meterdisplay 35 is formed of, for example, a liquid crystal panel. The imagedisplayed on the meter display 35 is controlled by the controller 10.

The meter display 35 displays an image showing the meter of thehost-vehicle. The image showing the meter includes a tachometer image 36showing the tachometer, and a speedometer image 37 showing thespeedometer. A left area of the entire area of the meter display 35displays the tachometer image 36, and a right area of the entire areadisplays the speedometer image 37.

The meter display 35 displays a second information image 38 showinginformation notified to the driver by the control system. The secondinformation image 38 is displayed in a central area of the entire areaof the meter display 35. That is, the second information image 38 isdisplayed at a space between the tachometer image 36, and thespeedometer image 37.

The tachometer and the speedometer may be formed of analog meters, andthe meter display 35 may display only the second information image 38.

The head-up display 40 is arranged in the instrument panel 3. Thehead-up display 40 displays the predetermined image such that the drivercan visually recognize the image by a remote display using a virtualimage. The display light emitted from the head-up display 40 isprojected on the windshield 4 through an opening (not shown) provided inthe instrument panel 3. The display light is reflected by the windshield4 to reach the eyepoint of the driver. This causes the driver tovisually recognize the virtual image at the outside of the windshield 4.In this way, the head-up display 40 emits the image toward thewindshield 4, and displays a virtual image obtained by the emittedimage, such that the virtual image is superimposed on the scene ahead ofthe host-vehicle

The head-up display 40 displays a first information image 41 showinginformation notified to the driver by the control system. The driver cansimultaneously visually recognize the first information image 41displayed by the head-up display 40, and the scene ahead of thehost-vehicle viewable through the windshield 4.

Referring to FIG. 3 , the first information image 41 displayed on thehead-up display 40, and the second information image 38 displayed on themeter display 35 will be described.

The first information image 41 is mainly composed of a preceding vehicleicon 41 a, a first character string 41 b, a mode display icon 41 c, afirst lane marker icon 41 d, and an arrow icon 41 e.

The preceding vehicle icon 41 a is a figure showing a preceding vehicletraveling on the same lane as the host-vehicle.

The first character string 41 b includes one or more characters such ashiragana characters, Chinese characters, numbers, and symbols, and is,for example, a sentence. Further, the first character string 41 b mayinclude emoji (a pictogram) that plays the same role as the character.

The first character string 41 b indicates the contents notified to thedriver by the control system. The contents of the first character string41 b may be the contents of a request from the control system, forexample, an operation instruction to the driver to perform the automaticlane change or the like. Alternatively, the contents of the firstcharacter string 41 b may be the control contents of what the controlsystem desires to perform, for example, the automatic lane change to beperformed. That is, the control system uses the first character string41 b to notify the driver of the request from the control system, orwhat the control system desires to perform. The first character string41 b has the relationship to be the same as a part of a second characterstring 38 b which will be described later.

The first character string 41 b is positioned above the precedingvehicle icon 41 a. More specifically, the first character string 41 b isarranged at the uppermost position among positions of elements formingthe first information image 41.

The mode display icon 41 c is a figure indicating whether a mode is ahands-off mode or a hands-on mode. The hands-off mode is a mode (a firstmode) in which the driver can release hands from the steering 1 duringautomatic driving. On the other hand, the hands-on mode is a mode (asecond mode) in which the driver needs to slightly touch the steering 1with the hands during automatic driving. The mode display icon 41 c hastwo kinds of figures that are a first steering figure and a secondsteering figure. The first steering figure shows only the steering, andthe second steering figure shows the steering and the hands slightlytouching the steering. The first steering figure is used, if a currentmode is the hands-off mode. The second steering figure is used, if thecurrent mode is the hands-off mode. The first steering figure isdisplayed in blue, for example, and the second steering figure isdisplayed in green (only a steering portion), for example.

The first lane marker icon 41 d is a figure showing left and right lanemarkers indicating boundaries of the host-vehicle lane. The left lanemarker indicated in the first lane marker icon 41 d indicates a boundarybetween the host-vehicle lane, and an adjacent lane or a road shoulderadjacent to the left side of the host-vehicle lane. Similarly, the rightlane marker indicated in the first lane marker icon 41 d indicates aboundary between the host-vehicle lane, and an adjacent lane or a roadshoulder adjacent to the right side of the host-vehicle lane.

The arrow icon 41 e is an arrow for guiding the automatic lane change.The arrow icon 41 e has a shape that bends in the middle from a base endside of the arrow (a lower side of the figure) to a tip side of thearrow (an upper side of the figure). Further, the arrow icon 41 eextends from the host-vehicle lane to the adjacent lane across the firstlane marker icon 41 d. That is, the arrow icon 41 e schematically showsa state in which the host-vehicle makes a lane change by the automaticlane change, and guides the automatic lane change.

The first information image 41 shows a travelling state of a vehicleahead of the host-vehicle with the preceding vehicle icon 41 a and thefirst lane marker icon 41 d. The first information image 41 is generatedso as to represent the travelling state of the vehicle ahead of thehost-vehicle when the driver looks in a forward direction.

In the first information image 41, the travelling state of the vehicleahead of the host-vehicle is shown two-dimensionally. This is becausethe first information image 41 is displayed on the head-up display 40.That is, by using a two-dimensional representation, the amount ofinformation is limited, and the visibility of the first informationimage 41 is enhanced.

The first information image 41 is generated at a predetermined timing,and each time the new first information image 41 is generated, the firstinformation image 41 displayed on the head-up display 40 is updated.

The first information image 41 does not need to always include all ofthe preceding vehicle icon 41 a, the first character string 41 b, themode display icon 41 c, the first lane marker icon 41 d, and the arrowicon 41 e. The first information image 41 may include some or all of thepreceding vehicle icon 41 a, the first character string 41 b, the modedisplay icon 41 c, the first lane marker icon 41 d, and the arrow icon41 e.

A real travelling state of an actually traveling host-vehicle isreflected in the travelling state of the vehicle ahead of thehost-vehicle shown in the first information image 41. Therefore, if thepreceding vehicle is not present actually, the first information image41 does not include the preceding vehicle icon 41 a.

The control contents of the control system are reflected in the firstcharacter string 41 b and the arrow icon 41 e. That is, if there is norequest from the control system, the first information image 41 does notinclude the first character string 41 b and the arrow icon 41 e.

The second information image 38 is mainly composed of a host-vehicleicon 38 a, a second character string 38 b, a second lane marker icon 38c, and a surrounding vehicle icon 38 d.

The host-vehicle icon 38 a is a figure indicating the host-vehicle.

The second character string 38 b includes one or more characters such ashiragana characters, Chinese characters, numbers and symbols, and is,for example, a sentence. Further, the second character string 38 b mayinclude emoji (a pictogram) that plays the same role as the character.

Similarly to the first character string 41 b, the second characterstring 38 b indicates the contents notified to the driver by the controlsystem. Specifically, the second character string 38 b includes thefirst character string 41 b and another character string (a thirdcharacter string). The contents of the third character string are thereason why the first character string 41 b is notified. That is, thecontrol system uses the second character string 38 b to notify thedriver of the request from the control system, or what the controlsystem desires to perform, and the reason thereof. The second characterstring 38 b has a larger amount of information than the first characterstring 41 b in that the second character string 38 b includes the thirdcharacter string in addition to the first character string 41 b.

In this way, the second character string 38 b includes the firstcharacter string 41 b. The inclusion of the first character string 41 bin the second character string 38 b does not mean that the element (thefirst character string 41 b) displayed on the first information image 41is regarded as a part of the second character string 38 b. Instead ofthe above, the above inclusion means that the second character string 38b includes a character string in which a string of characters is thesame as the first character string 41 b. However, the second characterstring 38 b described above is merely an example, and may be composed ofany characters (sentences) without being restricted by such conditions.

The second character string 38 b is positioned below the host-vehicleicon 38 a. In other words, the second character string 38 b is arrangedat the lowermost position among positions of the elements forming thesecond information image 38.

The second lane marker icon 38 c is a figure indicating lane markersshowing boundaries of one or more lanes in the road on which thehost-vehicle travels.

The surrounding vehicle icon 38 d is a figure showing a surroundingvehicle traveling around the host-vehicle. The surrounding vehicleincludes the preceding vehicle, and an adjacent vehicle traveling on theadjacent lane.

The second information image 38 shows travelling states of thehost-vehicle, and a vehicle around the host-vehicle with thehost-vehicle icon 38 a, the second lane marker icon 38 c, and asurrounding vehicle icon 38 d. The surroundings of the host-vehicleinclude each of a space in a forward direction of the host-vehicle,spaces in left and right lateral directions of the host-vehicle, and aspace in a backward direction of the host-vehicle. The secondinformation image 38 is generated so as to represent the travellingstate of the vehicle around the host-vehicle when the host-vehicle isviewed from positions above and behind the host-vehicle. It is enough ifthe viewpoint showing the travelling state is at least above thehost-vehicle, because the purpose is to grasp the travelling state ofthe vehicle around the host-vehicle.

In the second information image 38, the travelling state of the vehiclearound the host-vehicle is shown three-dimensionally. The use of thethree-dimensional representation further increases the amount ofinformation than the two-dimensional representation. Accordingly, thesecond information image 38 can deliver more various pieces ofinformation to the driver than the first information image 41.

The second information image 38 is generated at a predetermined timing,and each time the new second information image 38 is generated, thesecond information image 38 displayed on the meter display 35 isupdated.

The second information image 38 does not need to always include all ofthe host-vehicle icon 38 a, the second character string 38 b, the secondlane marker icon 38 c, and the surrounding vehicle icon 38 d. The secondinformation image 38 may include a part or all of the host-vehicle icon38 a, the second character string 38 b, the second lane marker icon 38c, and the surrounding vehicle icon 38 d.

The real travelling state of the actually traveling host-vehicle isreflected in the travelling state of the vehicle around the host-vehicleshown by the second information image 38. Therefore, if the surroundingvehicle is not present actually, the second information image 38 doesnot include the surrounding vehicle icon 38 d. Further, the second lanemarker icon 38 c corresponds to the number of lanes in the road on whichthe host-vehicle actually travels.

The control contents of the control system are reflected in the secondcharacter string 38 b. That is, if there is no request from the controlsystem, the second information image 38 does not include the secondcharacter string 38 b.

Referring again to FIG. 1 , the controller 10 will be described indetail. The controller 10 includes, as the plurality of informationprocessing circuits, a route generation unit 11, an automatic travelingprocessing unit 12, a vehicle control unit 13, an image generation unit14, a display control unit 15, a speaker control unit 16, and a winkercontrol unit 17.

The route generation unit 11 generates a route to a destination presetby the driver. The route generation unit 11 outputs the generated routeto the automatic traveling processing unit 12. The route generation unit11 may acquire a route generated by an external device.

The automatic traveling processing unit 12 performs various processesnecessary for performing the automatic lane change. The automatic lanechange includes a state of a system proposal in which the automatictraveling processing unit 12 (the control system) makes the proposal tothe driver to perform the automatic lane change, and a state of a driverproposal in which the automatic lane change is performed in response tothe reception of the proposal made by the driver.

The automatic lane change proposed by the system occurs if it isdetermined that a lane change is necessary to overtake the precedingvehicle. In addition to the above, the automatic lane change proposed bythe system occurs if it is determined that the lane change is necessaryto maintain the route generated by the route generation unit 11. On theother hand, the automatic lane change proposed by the driver occurs ifthe driver operates the winker switch 26 in a direction of a lane towhich the driver desires to move.

The automatic traveling processing unit 12 calculates a position of thehost-vehicle, a position of the surrounding vehicle, a relative speedbetween the host-vehicle and the preceding vehicle, and the like basedon pieces of information output by the host-vehicle position estimatingdevice 20, the map acquisition device 21, the surrounding informationdetection device 22, and the vehicle speed sensor 23. The automatictraveling processing unit 12 performs necessary calculations based onthe position of the host-vehicle, the position of the surroundingvehicle, the relative speed between the host-vehicle and the precedingvehicle, the route generated by the route generation unit 11, and thelike. The calculations made by the automatic traveling processing unit12 also use pieces of information output by the steering switch 24, thetouch sensor 25, and the winker switch 26. Further, the automatictraveling processing unit 12 outputs control commands necessary for theautomatic lane change, and processes associated therewith to the vehiclecontrol unit 13, the image generation unit 14, the display control unit15, the speaker control unit 16, and the winker control unit 17.

The vehicle control unit 13 controls the steering actuator 30 and thelike in response to the control command from the automatic travelingprocessing unit 12. The steering actuator 30 or the like operates inaccordance with the control by the vehicle control unit 13. Accordingly,the behavior of the host-vehicle is controlled, and this enablesperforming of the automatic lane change.

The image generation unit 14 generates the first information image 41and the second information image 38. The first information image 41 isgenerated so as to represent the travelling state of the vehicle aheadof the host-vehicle based on pieces of information output by thehost-vehicle position estimating device 20, the map acquisition device21, the surrounding information detection device 22, and the vehiclespeed sensor 23. Similarly, the second information image 38 is generatedso as to represent the travelling state of the vehicle around thehost-vehicle based on the pieces of information output by thehost-vehicle position estimating device 20, the map acquisition device21, the surrounding information detection device 22, and the vehiclespeed sensor 23.

In addition, the image generation unit 14 generates the firstinformation image 41 so as to include the first character string 41 bbased on the control command from the automatic traveling processingunit 12, that is, information to be notified to the driver. Similarly,the image generation unit 14 generates the second information image 38so as to include the second character string 38 b based on the controlcommand from the automatic traveling processing unit 12, that is, theinformation to be notified to the driver.

The display control unit 15 displays the first information image 41generated by the image generation unit 14 on the head-up display 40.Further, the display control unit 15 displays the second informationimage 38 generated by the image generation unit 14 on the meter display35.

The speaker control unit 16 controls a speaker 33 in response to thecontrol command from the automatic traveling processing unit 12. Bybeing controlled by the speaker control unit 16, the speaker 33 outputsa notification sound to the driver.

The winker control unit 17 controls the winker 34 in response to thecontrol command from the automatic traveling processing unit 12. Thecontrol of the winker 34 by the speaker control unit 16 operates eitherleft or right winker 34.

A display control device according to the present embodiment includesthe image generation unit 14 and the display control unit 15 among theplurality of information processing circuits constituting the controller10. A display control method according to the present embodimentincludes various processes performed by the image generation unit 14 andthe display control unit 15.

Hereinafter, with reference to FIGS. 4A and 4B, flows of the automaticlane change proposed by the system will be described by taking anexample of a situation in which the host-vehicle overtakes the precedingvehicle.

As shown in FIG. 4A, a host-vehicle 100 performs the automatic lanechange from a first lane L1 to a second lane L2 adjacent to the rightside of the first lane L1 in order to overtake a preceding vehicle 110traveling on the first lane L1. In this automatic lane change, controlflows by the automatic traveling processing unit 12 include thefollowing.

(1) The unit proposes the driver to perform the automatic lane change (atiming ta1).

(2) The unit receives the driver's consent to perform the automatic lanechange (a timing ta2).

(3) Prior to the start of the automatic lane change, the unit actuatesthe winker 34 in a direction of a lane to which the host-vehicle is tobe moved (a timing ta3).

(4) The unit completes the automatic lane change (a timing ta4)

As shown in FIG. 4B, the host-vehicle 100 performs the automatic lanechange from the second lane L2 to the first lane L1 after overtaking thepreceding vehicle 110 by travelling on the second lane L2. In thisautomatic lane change, control flows by the automatic travelingprocessing unit 12 include the following.

(1) The unit proposes the driver to perform the automatic lane change (atiming ta5)

(2) The unit receives the driver's consent to perform the automatic lanechange (a timing tab)

(3) Prior to the start of the automatic lane change, the unit actuatesthe winker 34 in a direction of a lane to which the host-vehicle is tobe moved (a timing ta7).

(4) The unit completes the automatic lane change (a timing ta8)

The control performed by the automatic traveling processing unit 12 inaccordance with the automatic lane change, and the processes associatedtherewith includes a plurality of processes as described above. Thefirst information image 41 displayed on the head-up display 40, and thesecond information image 38 displayed on the meter display 35 arechanged depending on each process of the control.

In the case of performing the automatic lane change from the first laneL1 to the second lane L2, the first information image 41 and the secondinformation image 38 are changed depending on five processes.

During a process up to the timing ta1, the first information image 41and the second information image 38 are mainly composed of contentsindicating the travelling state (FIG. 5A). During a process from thetiming ta1 to before the timing ta2, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents for proposing theautomatic lane change to the driver (FIG. 5B). During a process from thetiming ta2 to before the timing ta3, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents indicating that thedriver's consent for the automatic lane change is received (FIG. 5C).During a process from the timing ta3 to before the timing ta4, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsindicating that the automatic lane change is performed (FIG. 5D). Duringa process at or after the timing ta4, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state (FIG. 5E).

In the case of performing the automatic lane change from the second laneL2 to the first lane L1, the first information image 41 and the secondinformation image 38 are changed depending on five processes.

During a process up to the timing ta5, the first information image 41and the second information image 38 are mainly composed of contentsindicating the travelling state (FIG. 6A). During a process from thetiming ta5 to before the timing ta6, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents for proposing theautomatic lane change to the driver (FIG. 6B). During a process from thetiming ta6 to before the timing ta7, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents indicating that thedriver's consent for the automatic lane change is received (FIG. 6C).During a process from the timing ta7 to before the timing ta8, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsindicating that the automatic lane change is performed (FIG. 6D). Duringa process at or after the timing ta8, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state (FIG. 6E).

As shown in FIGS. 5A to 5E, and FIGS. 6A to 6E, the first informationimage 41 includes the preceding vehicle icon 41 a, and the first lanemarker icon 41 d, and shows the travelling state of the vehicle ahead ofthe host-vehicle 100. Further, the second information image 38 includesthe host-vehicle icon 38 a, the second lane marker icon 38 c, and thesurrounding vehicle icon 38 d, and shows the travelling state of thevehicle around the host-vehicle 100.

The first information image 41 includes the first character string 41 b,and the second information image 38 includes the second character string38 b. An example of the first character string 41 b and the secondcharacter string 38 b will be described below.

In FIG. 5B, the first character string 41 b is a character string“(Pictogram) Move to a right lane by lane change”. The pictogram in thefirst character string 41 b corresponds to a pictogram marked on thesteering switch 24, and has the meaning to urge the operation of thesteering switch 24 (the same applies hereinafter). The character string“(Pictogram) Move to a right lane by lane change” proposes the automaticlane change to the driver.

In FIG. 5B, the second character string 38 b includes a character string“A slowly travelling vehicle is present in a forward direction”, acharacter string “Confirm the safety”, and a character string“(Pictogram) Move to a right lane by lane change”. The character string“(Pictogram) Move to a right lane by lane change” indicates contents forproposing the automatic lane change to the driver. The character string“A slowly travelling vehicle is present in a forward direction”indicates the reason why the automatic lane change is proposed. Thecharacter string “Confirm the safety” indicates the contents forproposing the safety confirmation to the driver. As described above, thesecond character string 38 b includes the first character string 41 b(“(Pictogram) Move to a right lane by lane change”). In other words, thefirst character string 41 b is the same as a part of the secondcharacter string 38 b.

On the other hand, in FIG. 6B, the first character string 41 b is acharacter string “(Pictogram) Move to a left lane by lane change”. Thecharacter string “(Pictogram) Move to a left lane by lane change”indicates contents for proposing the automatic lane change to thedriver.

In FIG. 6B, the second character string 38 b includes a character string“Confirm the safety” and a character string “(Pictogram) Move to a leftlane by lane change”. The character string “(Pictogram) Move to a leftlane by lane change” indicates contents for proposing the automatic lanechange to the driver. The character string “Confirm the safety”indicates contents for proposing the safety confirmation to the driver.In this way, the second character string 38 b includes the firstcharacter string 41 b.

However, the display scene in FIG. 6B corresponds to the lane changefrom the second lane L2 to the first lane L1 (second automatic lanechange) following the lane change from the first lane L1 to the secondlane L2 (first automatic lane change). The second automatic lane changeis performed to return to the first lane L1 on which the host-vehicle100 was originally travelling. Therefore, it is considered that thedriver has already grasped the reason why the second automatic lanechange is performed. Accordingly, in the case of the second automaticlane change, the second character string 38 b does not include acharacter string indicating a reason.

The image generation unit 14 and the display control unit 15 generateand display the first information image 41 and the second informationimage 38 in response to the control command from the automatic travelingprocessing unit 12, as described above. At this time, the displaycontrol unit 15 displays the first information image 41 and the secondinformation image 38 such that the first character string 41 b and thesecond character string 38 b are displayed at the same time.

The speaker control unit 16 controls the speaker 33 in response to thecontrol command from the automatic traveling processing unit 12. Thiscauses the speaker 33 to output the notification sound to the driver inaccordance with the display of the first character string 41 b and thesecond character string 38 b.

Next, with reference to FIG. 7 , flows of the automatic lane changeproposed by the system will be described by taking an example of asituation in which the route generated by the route generation unit 11is maintained. In order to reach an exit path L4 branching from a mainroad, the host-vehicle 100 performs the automatic lane change from athird lane L3 to the second lane L2, then, from the second lane L2 tothe first lane L1, and then from the first lane L1 to the exit path L4.

In this automatic lane change, control flows of the automatic travelingprocessing unit 12 include the following.

(1) The unit proposes the driver to perform the automatic lane change (atiming tb1).

(2) The unit receives the driver's consent to perform the automatic lanechange (a timing tb2)

(3) Prior to the start of the automatic lane change to the second laneL2, the unit actuates the winker 34 in a direction of a lane to whichthe host-vehicle is to be moved (a timing tb3).

(4) The unit completes the automatic lane change to the second lane L2(a timing tb4).

(5) Prior to the start of the automatic lane change to the first laneL1, the unit actuates the winker 34 in a direction of a lane to whichthe host-vehicle is to be moved (a timing tb5).

(6) The unit completes the automatic lane change to the first lane L1 (atiming tb6).

(7) The unit determines that the distance between a branch point of theexit path L4, and the host-vehicle 100 becomes a predetermined firstdistance (a timing tb7).

(8) Prior to the start of the automatic lane change to the exit path L4,the unit actuates the winker 34 in a direction of the exit path L4 towhich the host-vehicle is to be travelled (a timing tb8).

(9) The unit determines that the host-vehicle 100 has reached the branchpoint (a timing tb9).

(10) The unit completes the automatic lane change to the exit path L4 (atiming tb 10).

The control performed by the automatic traveling processing unit 12 inaccordance with the automatic lane change, and the processes associatedtherewith includes a plurality of processes as described above. Thefirst information image 41 displayed on the head-up display 40, and thesecond information image 38 displayed on the meter display 35 arechanged depending on each process of the control.

In the automatic lane change from the third lane L3 to the exit path L4,the first information image 41 and the second information image 38 arechanged depending on 11 processes.

During a process up to the timing tb1, the first information image 41and the second information image 38 are mainly composed of contentsindicating the travelling state (not shown). During a process from thetiming tb1 to before the timing tb2, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents for proposing theautomatic lane change to the driver (FIG. 8A). During a process from thetiming tb2 to before the timing tb3, the first information image 41 andthe second information image 38 are mainly composed of the contentsindicating the travelling state, and contents indicating that thedriver's consent for the automatic lane change is received (FIG. 8B).During a process from the timing tb3 to before the timing tb4, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsindicating that the automatic lane change is performed (FIG. 8C).

During a process from the timing tb4 to before the timing tb5, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsfor notifying the second automatic lane change (FIG. 8D). During aprocess from the timing tb5 to before the timing tb6, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsindicating that the automatic lane change is performed (FIG. 8E). Duringa process from the timing tb6 to before the timing tb7, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsindicating that the automatic lane change is continuously performed(FIG. 8F).

During a process from the timing tb7 to before the timing tb8, the firstinformation image 41 and the second information image 38 are mainlycomposed of the contents indicating the travelling state, and contentsfor notifying that the host-vehicle will travel to the exit path L4(FIG. 8G). During a process from the timing tb9 to before the timingtb10, the first information image 41 and the second information image 38are mainly composed of the contents indicating the travelling state, andcontents indicating that the automatic lane change is performed (FIG.8H). During a process at or after the timing tb10, the first informationimage 41 and the second information image 38 are mainly composed of thecontents indicating the travelling state (FIG. 8I).

As shown in FIGS. 8A to 8I, the first information image 41 includes thepreceding vehicle icon 41 a, and the first lane marker icon 41 d, andshows the travelling state of the vehicle ahead of the host-vehicle 100.Further, the second information image 38 includes the host-vehicle icon38 a, the second lane marker icon 38 c, and the surrounding vehicle icon38 d, and shows the travelling state of the vehicle around thehost-vehicle 100.

The first information image 41 includes the first character string 41 b,and the second information image 38 includes the second character string38 b. An example of the first character string 41 b and the secondcharacter string 38 b will be described below.

In FIG. 8B, the first character string 41 b is a character string“(Pictogram) Travel toward an exit”. The character string “(Pictogram)Travel toward an exit” indicates contents for proposing the automaticlane change to the driver.

In FIG. 8B, the second character string 38 b includes a character string“There will be an exit in a forward left direction”, a character string“Confirm the safety”, and a character string “(Pictogram) Travel towardan exit”. The character string “(Pictogram) Travel toward an exit”indicates contents for proposing the automatic lane change to thedriver. The character string “There will be an exit in a forward leftdirection” indicates the reason why the automatic lane change isproposed. The character string “Confirm the safety” indicates contentsfor proposing the safety confirmation to the driver. As described above,the second character string 38 b includes the first character string 41b (“(Pictogram) Travel toward an exit”). In other words, the firstcharacter string 41 b is the same as a part of the second characterstring 38 b.

On the other hand, in FIG. 8D, the first character string 41 b is acharacter string “Change a lane continuously”. The character string“Change a lane continuously” indicates contents for notifying that theautomatic lane change will be continuously performed.

In FIG. 8D, the second character string 38 b includes the characterstring “Change a lane continuously” and a character string “(Pictogram)Make cancellation by long press”. The character string “Change a lanecontinuously” indicates the contents for notifying that the automaticlane change will be continuously performed. The character string“(Pictogram) Make cancellation by long press” indicates contents fornotifying how to stop the automatic lane change. Therefore, the secondcharacter string 38 b includes the first character string 41 b.

However, the display scene in FIG. 8D corresponds to the lane changefrom the second lane L2 to the first lane L1 (the second automatic lanechange) following the lane change from the third lane L3 to the secondlane L2 (the first automatic lane change). Therefore, it is consideredthat the driver has already grasped the reason why the second automaticlane change is performed. Accordingly, in the case of the secondautomatic lane change, the second character string 38 b does not includea character string indicating the reason.

Different forms of the first information image 41 and the secondinformation image 38 will be described below.

With reference to FIG. 9 , different forms of the second informationimage 38 will be described. The automatic traveling processing unit 12performs the linkage control (navigation linkage control) for causingthe host-vehicle to travel by linking with the route generated by theroute generation unit 11. The automatic traveling processing unit 12performs the above described automatic lane change in the linkagecontrol. However, when determining a predetermined condition, forexample, a traffic congestion, the automatic traveling processing unit12 prohibits the function of the automatic lane change.

In a case of a time period during which the automatic lane change maynot be performed, the second character string 38 b of the secondinformation image 38 indicates contents of the control state currentlyperformed by the automatic traveling processing unit 12. In FIG. 9 , thesecond character string 38 b is a character string “Nav linkage controlis in progress (pictogram)” which indicates that the navigation linkagecontrol is being performed. The “nav linkage control” is an abbreviationof the navigation linkage control.

In this case, the second character string 38 b is in a transparentstate, and is displayed such that the character string 38 b issuperimposed on other elements included in the second information image38, such as for example, the lane marker 3 c.

Next, different forms of the first information image 41 and the secondinformation image 38 will be described. The control system has two modesthat are the hands-off mode and the hands-on mode. If a transitioncondition of the transition to the hands-on mode is established duringthe hands-off mode, the image generation unit 14 and the display controlunit 15 perform the predetermined display for urging the driver to holdthe steering.

Specifically, the image generation unit 14 and the display control unit15 generate and display the first information image 41 and the secondinformation image 38, such that the first character string 41 b and thesecond character string 38 b are displayed at the same time. Forexample, as shown in FIG. 10 , the first character string 41 b is acharacter string “Hold a handle”. The second character string 38 bincludes the character string “Hold a handle” and a character string“There will be a merging section”.

As described above, in the display control method according to thepresent embodiment, the first information image (a first image) isdisplayed on the head-up display 40. The first information image 41includes the preceding vehicle icon 41 a and the first character string41 b arranged above the preceding vehicle icon 41 a. Further, in thedisplay control method, the second information image (a second image) 38is displayed on the meter display 35. The second information image 38includes the host-vehicle icon 38 a and the second character string 38 bwhich is arranged below the host-vehicle icon 38 a and includes thefirst character string 41 b.

The driver moves a visual line from a forward direction to a lowerdirection of the host-vehicle to visually recognize the firstinformation image 41 of the head-up display 40. If the driver visuallyrecognizes the second information image 38 of the meter display 35, thedriver needs to move the visual line further downward than the head-updisplay 40. In this way, the head-up display 40 can transmit informationto the driver with less visual line movement than the meter display 35.Irrespective of such the difference in visibility characteristics, asdescribed below, the driver can properly grasp pieces of informationfrom the head-up display 40 and the meter display 35.

In the first information image 41 displayed on the head-up display 40,the first character string 41 b is arranged above the preceding vehicleicon 41 a. Therefore, the driver visually recognizes the first characterstring 41 b before the other element in the first information image 41.This can cause the driver to positively visually recognize the firstcharacter string 41 b. In addition, the first character string 41 b hasa smaller amount of information (the number of characters) than thesecond character string 38 b of the second information image 38.Therefore, the driver can easily read the first character string 41 b.

In the display area of the meter display 35, the second character string38 b is arranged below the host-vehicle icon 38 a. When moving thevisual line downward to view the second information image 38, the driverfirst visually recognizes the host-vehicle icon 38 a, and then visuallyrecognizes the second character string 38 b. The driver visuallyrecognizes the first information image 41 of the head-up display 40 inadvance. Therefore, the driver already grasps a part (the firstcharacter string 41 b) of the second character string 38 b displayed onthe second information image 38. Accordingly, when the secondinformation image 38 is visually recognized by the driver, informationof the host-vehicle icon 38 a displayed on the second information image38 can be positively visually recognized by the driver by causing thedriver to visually recognize the host-vehicle icon 38 a before the otherelement. In addition, the second character string 38 b can includecharacter strings other than the first character string 41 b.Accordingly, the driver can receive the first character string 41 b in aconfirmed manner, and also the unique information of the secondcharacter string 38 b.

Further, in the display control method according to the presentembodiment, the first character string 41 b indicates the contentsnotified to the driver by the control system. The second characterstring 38 b includes the first character string 41 b, and the thirdcharacter string indicating the reason why the first character string 41b is notified. The third character string is displayed only on the meterdisplay 35.

The driver can recognize the reason why the first character string 41 bis notified by visually recognizing the second character string 38 b.Further, the head-up display 40 is requested to display only the minimumnecessary information. By displaying the third character string only onthe meter display 35, necessary information can be notified to thedriver while satisfying the above request for the head-up display 40.

In the display control method according to the present embodiment, thefirst information image 41 is displayed on the head-up display 40, andthe second information image 38 is displayed on the meter display 35,such that the first character string 41 b and the second characterstring 38 b are displayed at the same time. In this case, in the displaycontrol method, the notification sound is output to the driver inaccordance with the display of the first character string 41 b and thesecond character string 38 b.

By outputting the notification sound, the consciousness of the drivercan be directed to the first character string 41 b and the secondcharacter string 38 b. This can cause the driver to effectivelyrecognize the first character string 41 b and the second characterstring 38 b.

When the display of the first character string 41 b and the secondcharacter string 38 b is ended, a reminder to the driver is unnecessary.Therefore, by outputting the notification sound only during the display,the number of times the notification sound is output can be suppressedto reduce the trouble felt by the driver. That is, in the displaycontrol method of the present embodiment, when the display of the firstcharacter string 41 b and the second character string 38 b is ended, thenotification sound is not output.

In the display control method according to the present embodiment, thepreceding vehicle icon 41 a indicates the preceding vehicle traveling onthe same lane as the host-vehicle. The first information image 41 showsthe travelling state of the vehicle ahead of the host-vehicle, when thedriver of the host-vehicle looks in the forward direction. On the otherhand, the host-vehicle icon 38 a indicates the host-vehicle. The secondinformation image 38 shows the travelling state of the vehicle aroundthe host-vehicle when the host-vehicle is viewed from above.

In the second information image 38, the travelling state is displayed oneach of the upper side, and right and left sides of the host-vehicleicon 38 a. By displaying the second character string 38 b below thehost-vehicle icon 38 a, the travelling state and the second characterstring 38 b can be displayed in a cooperative manner.

Further, the second information image 38 displays the travelling state,when the vehicle is viewed from a position behind the host-vehicle.Therefore, there is a margin below the host-vehicle icon 38 a. On theother hand, in the first information image 41, the preceding vehicle istwo-dimensionally displayed in the viewpoint of the driver. Therefore,there is a margin above the preceding vehicle icon 41 a. The arrangementof character strings is optimized depending on characteristics of eachof the information images, and therefore, information can beappropriately notified to the driver.

In the display control method according to the present embodiment, in acase of a time period during which the control system may not performthe automatic lane change, the second character string 38 b indicatescontents of the control state currently performed by the control system.In this case, the second character string 38 b is in a transparentstate, and is displayed such that the second character string 38 b issuperimposed on other elements included in the second information image38.

Even if the function of the automatic lane change is limited, the drivercan recognize the current control state from the second character string38 b. Further, the display that causes the trouble felt to the drivercan be suppressed, because the second character string 38 b in atransparent state is displayed in a superimposed manner.

Further, in the display control method according to the presentembodiment, if the control system proposes the automatic lane change tothe driver, the first information image 41 is displayed on the head-updisplay 40, and the second information image 38 is displayed on themeter display 35 such that the first character string 41 b and thesecond character string 38 b are displayed at the same time.

This method can appropriately notify the driver of information on theautomatic lane change.

In the display control method according to the present embodiment,contents of the automatic lane change proposed to the driver by thecontrol system include the first automatic lane change, and the secondautomatic lane change performed following the first automatic lanechange. In this case, the second character string 38 b displayed in thefirst automatic lane change includes the first character string 41 b,and the third character string indicating the reason why the firstcharacter string 41 b is notified. On the other hand, the secondcharacter string 38 b displayed in the second automatic lane changeincludes the first character string 41 b, but does not include the thirdcharacter string.

In the second automatic lane change, the driver obviously recognizes thereason why the automatic lane change is performed, because the firstautomatic lane change is already performed. Therefore, by the secondcharacter string 38 b corresponding to the second automatic lane changenot including the third character string, the display causing thetrouble felt to the driver can be reduced.

The display control method according to the present embodiment includesa case where the transition condition of the transition to the hands-onmode is established during the hands-off mode. In this case, in thedisplay control method, the first information image 41 and the secondinformation image 38 are displayed, such that the first character string41 b and the second character string 38 b are displayed at the sametime. The first character string 41 b includes contents for urging thedriver to hold the steering 1.

This can urge the driver to hold the steering 1 in accordance with thetransition from the hands-off mode to the hands-on mode.

The display control device according to the present embodiment includesthe controller 10 that controls the head-up display 40, and the meterdisplay 35. The controller 10 displays, on the head-up display 40, thefirst information image (the first image) 41. The first informationimage 41 includes the preceding vehicle icon 41 a, and the firstcharacter string 41 b arranged above the preceding vehicle icon 41 a.Further, the controller 10 displays, on the meter display 35, the secondinformation image (the second image) 38. The second information image 38includes the host-vehicle icon 38 a, and the second character string 38b that is arranged below the host-vehicle icon 38 a, and includes thefirst character string 41 b.

The display control device according to the present embodiment has atechnical feature corresponding to the display control method describedabove, and has the same effect as the display control method.

The present invention is not limited to the present embodiment describedabove, and various modifications can be made without departing from thescope of the present invention.

For example, in the first image displayed on the head-up display, it isenough if a vehicle icon is a figure representing a vehicle, and theicon is not limited to a figure representing a preceding vehicle.Further, in the second image displayed on the meter display, it isenough if a vehicle icon is a figure representing a vehicle, and theicon is not limited to a figure representing a host-vehicle.

REFERENCE SIGNS LIST

-   -   10 Controller    -   11 Route generation unit    -   12 Automatic traveling processing unit    -   13 Vehicle control unit    -   14 Image generation unit    -   15 Display control unit    -   16 Speaker control unit    -   17 Winker control unit    -   20 Host-vehicle position estimating device    -   21 Map acquisition device    -   22 Surrounding information detection device    -   23 Vehicle speed sensor    -   24 Steering switch    -   25 Touch sensor    -   26 Winker switch    -   30 Steering actuator    -   31 Accelerator pedal actuator    -   32 Brake actuator    -   33 Speaker    -   34 Winker    -   35 Meter display    -   40 Head-up display

The invention claimed is:
 1. A display control method used for a control system that controls a behavior of a host-vehicle to perform an automatic lane change, the display control method comprising: when the control system proposes to a driver to perform the automatic lane change, displaying a first image that is a first vehicle icon that is a first vehicle figure and a first character string that proposes the automatic lane change to the driver on a head-up display that displays an image superimposed on a scene ahead of the host-vehicle; displaying a second image that is a second vehicle icon that is a second vehicle figure and a second character string that includes at least the first character string on a meter display provided to a meter unit that displays a meter of the host-vehicle; and displaying a third character string indicating a reason why the first character string is notified only on the meter display, wherein: when contents of the automatic lane change proposed to the driver by the control system include a first lane change and a second lane change following the first lane change, the second character string displayed in the first lane change includes the first character string and the third character string, and the second character string displayed in the second lane change includes the first character string, but does not include the third character string.
 2. The display control method according to claim 1, further comprising: displaying the second image on the meter display such that the first character string and the second character string are displayed at a same time; and notifying with a notification sound to the driver that the first character string and the second character string are displayed.
 3. The display control method according to claim 1, wherein the first vehicle icon indicates a preceding vehicle that travels on a same lane as the host-vehicle; the first image shows a travelling state of the preceding vehicle ahead of the host-vehicle when the driver of the host-vehicle looks in a forward direction; the second vehicle icon indicates the host-vehicle; and the second image shows a travelling state of a vehicle around the host-vehicle when the host-vehicle is viewed from above.
 4. The display control method according to claim 1, wherein, in a case of a time period during which the control system may not perform the automatic lane change, the second character string indicates contents of a control state currently performed by the control system.
 5. The display control method according to claim 4, wherein the second character string is transparent and is displayed such that the second character string is superimposed on another element included in the second image.
 6. The display control method according to claim 1, wherein, when the control system proposes the automatic lane change to the driver, the first character string and the second character string are displayed at a same time.
 7. The display control method according to claim 1, wherein; when a transition condition of a transition to a second mode is established during a first mode, the second mode being a mode in which the driver needs to slightly touch a steering with a hand, and the first mode being a mode in which the driver can release the hand from the steering, the first character string and the second character string are displayed at a same time; and the first character string includes contents for urging the driver to hold the steering.
 8. The display control method according to claim 1, further comprising: providing a switch to a steering of the host-vehicle, the switch configured to receive a consent of the driver for the automatic lane change after the automatic lane change is proposed by the control system.
 9. The display control method according to claim 1, wherein the first character string is arranged one of above or below the first vehicle icon and the second character string is arranged another of above or below the second vehicle icon.
 10. A display control device used for a control system that controls a behavior of a host-vehicle to perform an automatic lane change, the display control device comprising: a controller that controls a head-up display that displays an image superimposed on a scene ahead of the host-vehicle and a meter display provided to a meter unit that displays a meter of the host-vehicle, wherein the controller is configured to: when the control system proposes to a driver to perform the automatic lane change, display a first image that is a first vehicle icon including a first vehicle figure and a first character string that proposes the automatic lane change to the driver on the head-up display; display a second image that is a second vehicle icon including a second vehicle figure and a second character string that includes at least the first character string on the meter display; and display a third character string indicating a reason why the first character string is notified only on the meter display, wherein: when contents of the automatic lane change proposed to the driver by the control system include a first lane change and a second lane change following the first lane change, the second character string displayed in the first lane change includes the first character string and the third character string; and the second character string displayed in the second lane change includes the first character string, but does not include the third character string.
 11. A display control method used for a control system that controls a behavior of a host-vehicle to perform a lane change, the display control method comprising: displaying a first image on a head-up display that displays an image superimposed on a scene ahead of the host-vehicle, wherein the first image includes a first vehicle icon that is a figure indicating a vehicle and a first character string arranged above the first vehicle icon; and displaying a second image on a meter display provided to a meter unit that displays a meter of the host-vehicle, wherein the second image includes a second vehicle icon that is a figure indicating a vehicle and a second character string that is arranged below the second vehicle icon, and wherein the second character string includes at least the first character string, wherein when the control system proposes a first lane change and a second lane change following the first lane change, the second character string displayed in the first lane change includes the first character string and a third character string, and the second character string displayed in the second lane change includes the first character string without the third character string. 